Boeing's HyFly hypersonic missile fails in bid for Mach 6 By Graham Warwick An attempt to fly a hypersonic cruise missile demonstrator at Mach 6 has failed, after the scramjet engine powering Boeing's HyFly malfunctioned and the air-launched vehicle plunged into the Pacific Ocean. The January 16 flight was the last under the HyFly programme, which was designed to demonstrate a missile-like vehicle with a range of 400nm (740km) and a maximum cruise speed exceeding Mach 6. The previous flight, in September 2007, failed to meet its objectives. The HyFly is powered by a dual-combustion ramjet (DCR) built by Aerojet....